Rail bond



April 7,1942. F. c. LAVARACK mp I 2,278,659

RAIL BOND Filed NOV. 28, 1939 /ZSIIIEIIII j Patented Apr. 7, 1942 RAIL BOND Application November 28, 1939, Serial No. 306,436

Claims. (01. 28720.3)

This invention relates to conductors, more es pecially to conductors for connecting the adjacent ends of railway rails, particularly those for use in connection with railway track circuits.

An object of the invention is to devise a bond, especially of the type specified, in which provision is made to insure a permanently firm contact between the outside surface of the thimble and the inside surface of an orifice in the ball of a rail particularly at the line of juncture between the thimble and the outside edge of the orifice.

A further object of the invention is to devise a bond especially of the type specified, in which provision is made to insure a fresh surface of the thimble being pressed in contact with the inside surface of the orifice in the ball of a rail.

Other objects and advantages will appear as the description of the particular physical embodiments selected to illustrate the invention progresses and the novel features will be particularly pointed out in the appended claims.

In describing the invention in detail and the particular physical embodiments selected to illustrate the invention, reference will be had to the accompanying drawing and the several views thereon, in which similar parts will be designated by similar characters throughout the several views and in which:

Figure 1 is a side elevational view of abutting rail end fragments with a bond of my invention in place therein; Fig. 2 is a top plan view of the device as shown by Fig. 1; Fig. 3 is a fragmentary cross-sectional view on the plane indicated by the line III-III of Fig. I viewed in the direc tion of the arrows at the ends of the line illustrating the parts after the thimble has been completely secured in place in an orifice in the ball of a rail; Fig. 4 is a view similar to Fig. 3 but illustrating the initiation of the securing of the thimble in the orifice in the ball of a rail; Fig. 5 illustrates the initiation of the securing of a thimble of a modified form in the ball of a rail.

In the drawing, numeral I designates one rail and numeral 2 designates an adjacent or abutting rail of a railway track. Each of these rails has a cavity as 3 formed, in any usual or preferred manner, as by drilling, in the outside face thereof. This cavity is of such diameter and of such depth as to just fail of encroaching upon the fissure area of the rail.

The bond. itself consists, in general, of an electrical conductor 4 having a terminal at each end. This electrical conductor 4 may be made of any suitable or appropriate material and in any proper form, but it is preferred to make it as a cable formed of a plurality of electrical conducting Wires with a suitable twist or helical turn to each of the separate wires so that when formed it is quite flexible and bendable.

The terminals, one at each end of the conductor are the parts of the bond exhibiting the new feature of applicants invention. a

As heretofore, the thimbles 5 of the terminals are made of any suitable or appropriate material somewhat softer than the steel of ordinary rails, preferably copper, and are formed in any suitable or appropriate manner as by stamping or drawing as heretofore.

Applicants thimble 5 differs from the thimbles of the prior art in that its outside diameter is made such that it will enter the standard sized orifice in the ball of a rail for a short distance only, as illustrated by Fig. 4, when inserted therein by hand.

After the thimble 5 has been inserted to the point indicated in Fig. 4 any suitable means, as

I a punch 6, applied to the outer surface of the pellet or plug 7 and having force applied thereto, as by a hammer, may be used to force the thimble 5 to its final position as shown in Fig. 3 in which operation both the end of the thimble and the pellet or'plug 1 are somewhat deformed.

As the thimble 5 is so made that it will only partially enter the orifice 3 in the ball of a rail, and then must be forced the remainder of the distance to arrive at the position as shown in Fig. 3, the outside surface of the thimble is brightened from the point 8 of Fig. 4 to the point 9 of Fig. 3 because the sharp edge of the orifice scrapes or shears the softer material of the thimble and so presents a freshly made bright surface to contact the interior surface of the orifice so that the thimble after reaching its final position contacts a portion of the orifice with its original unchanged outer surface and is held tightly in contact therewith by the expanded pellet. A further surface forming a zone around the thimble ending in the plane of the outer surface of the deformed pellet which has been freshly brightened contacts the interior surface of the orifice in the ball of the rail and a further zone of the outer surface of the thimble of freshly brightened surface extending from the termination of the first zone to the plane of the outside surface of the face of the ball of the rail contacts a corresponding surface of the orifice in the ball of the rail and is pressed thereto merely by the inherent resiliency of the material of the thimble because the outside surface of the deformed pellet 7 is interior of the plane of the outside face of the ball of the rail.

The newly brightened surface and shearing of the material of the thimble may be obtained by making the thimble as shown in Fig. 4 with a taper from the point 8 to the point l0 so that the diameter at the point I0 is greater than at the point 8 or as shown in Fig. 5, the outside diameter of the thimble ll may be abruptly changed at the point l2 to become larger as along the line l3. Of course, the form shown in Fig. 4 may taper all the way from joint I! to point Hi. In the case of either form of thimble, material will be sheared from the outer surface and a freshly brightened surface presented by driving the thimble home to the position as shown in Fig. 3.

Not only does the outer surface of the thimble. as 5 or H become brightened and present a fresh surface but the inside surface of the orifice 3 for a portion of its length is also scraped or scoured by the forcible passage thereover of the outside surface of the thimble so that the inside surface of the Orifice also becomes somewhat cleaned and brightened so that by the time the thimble has been completely driven home, the contact surface of both the first and second mentioned zones are contacting surface of substantially freshly brightened surfaces.

The completely installed terminal is unlike the completely installed terminal of Patent No. 2,045,126 because the pellet I was selected of such dimensions that when fully driven home the forward Or outward face I4 is substantially back of the plane 15 of the outside surface of the ball of the rail so that the thimble is not Dressed by the pellet into the corner edge of the orifice. In this respect the construction is that of Patent No. 1,945,480 dated January 30, 1934, granted to Deems. However, the metal of the thimble has been forced by applicants method and construction into very close and intimate contact with the edge of the orifice 3 and thereby one might predict more chance for breakage of the thimble at this point due to vibration. This may well be taken care of, however, and the general efliciency of the thimble increased by increasing the thickness of the metal of the thimble beyond what has been usually used in comparable thimbles following the old principles. Definite gauge of thickness of metal cannot well be given because the thickness will have to be adjusted in accordance with the characteristics of the particular metal used for making the thimble and the gauge be such that firm contact will exist between the thimble and the inside surface of the orifice adjacent the edge of the hole but no substantial breakage occur by reason of vibration, all of which may be readily determined for any particular metal by a few experiments.

It will be noted by reference to Fig. 3, that a very slight shoulder I5 is formed on the thimble 5 by the driving operation. It is believed that this slight shoulder substantially reduces the opportunity for foreign material, liquid or solid, to work its way between the thimble and the inside surface of the orifice 3 and so results in a longer efficient life for the bond before the electrical contact surfaces deteriorate.

Although we have particularly described several particular physical embodiments of our invention and explained the operation, construction and principle thereof, nevertheless, We desire to have it understood that the forms selected are merely illustrative, but do not exhaust the possible physical embodiments of the idea of means underlying our invention.

What we claim as new and desire to secure by Letters Patent of the United States, is:

1. A rail bond, having in combination: a rail formed with a predetermined size orifice; a conductor; thimbles, one attached to each end of the conductor, each thimble having a portion of such outside diameter as to enable it to partially enter the orifice formed in a rail, and having a further portion of such outside diameter that further movement into the orifice shears material from the outside surface of the thimble whereby a fresh surface is presented for contact with the inside surface of the orifice in a rail and a deformable pellet positioned in the thimble of such dimensions that when driven fully the outer surface is inwardly of the line of juncture of the thimble and edge of the orifice in the rail.

2. A bond for a rail having a predetermined size bond orifice therein which bond comprises, in combination: a conductor, thimbles, one attached to each end of the conductor, each thimble having a portion of an outside diameter in relation to the diameter of the bond orifice such that the thimble will only partially enter the orifice, and having a further portion displaced from the first mentioned portion longitudinally of the thimble of an outside diameter in relation to the diameter of the bond orifice such that entrance into the bond orifice shears material from the outside surface of the thimble whereby a fresh surface on the thimble contacts with the inside surface of the bond orifice of the rail and a deformable pellet positioned in the thimble of such volume that when driven fully the outer surface thereof is inwardly of the line of juncture of the thimble and edge of the orifice in the rail.

3. A rail bond adapted for attachment to an electrical conducting metallic rail having a predetermined size orifice therein having in combination: an electrical conductor; electrical conducting metallic thimbles, one electrically attached to each end of the conductor, each thimble having a portion of such outside diameter as to enable it to partially enter the orifice formed in the rail, and having a further portion of such outside diameter that further movement into the orifice shears material from the outside surface of the thimble whereby a contact is established between the outside surface of the thimble and. the inside surface of the orifice which includes 'a fresh surface of the thimble and a deformable metallic pellet positioned in the thimble, said pellet being of such volume that when driven fully the outer surface is inwardly of the line of juncture of the thimble and edge of the orifice in the rail.

4. A thimble serving as the terminal of an electrical bond for attachment to a predetermined size orifice in an electrical conducting metallic rail, said thimble formed of electrically conducting material and formed of one diameter adjacent its closed end and of a larger diameter for the remainder of its outside surface whereby the closed end may be partially entered into the orifice in a rail without substantial pressure application and the further portion of enlarged diameter may be entered in the orifice in the rail by the application of force sufficient to shear material from the outside surface of the thimble and present a fresh surof one diameter and a portion more remote therefrom of a greater diameter, the first mentioned diameter substantially approximating that of the orifice in which the terminal is to be 5 inserted.

FREDERICK C. LAVARACK. EDWARD M. DEEMS. 

